The NCRP’s safety guidelines for diagnostic ultrasound are designed to try to prevent cavitation
effects, because these effects can be damaging. Restrictions on the pressure amplitude of the ultrasound
pulse, in combination with awareness of whether or not there are gas bubbles in the tissue being imaged,
can help to prevent cavitation. Other factors such as the length of the pulse, and the density of the liquid,
also influence whether or not cavitation occurs. And if there are gas bubbles, the number, size and location
of the bubbles also contribute to the effect.